Flexible strip door systems, having a plurality of vertically hanging flexible strips with longitudinal edges in either abutting or overlapping arrangement, are used in many varied applications as a barrier in a vertical plane, while still allowing for substantially free movements of personnel, equipment, product, or the like through the barrier by simply parting and/or bending the hanging flexible strips. Throughout this document the terminology “strip door” is found, however in certain applications in the field of the invention the terminology “strip curtain” is used. The present invention is applicable to all types of installations using flexible plastic strips. Examples of where flexible strip door systems are utilized include: entryways into coolers, freezers, heated/cooled rooms, and processing areas; loading doors for entry onto loading docks; openings of product display cases in supermarkets; areas of high heat output within a production area; and areas within a production area at which fumes, particulate matter, liquid droplets, etc. are to be contained. Although flexible strip door systems are used to a large extent as a barrier to the movement of air across a selected vertical plane, which can lead to a substantial savings in heating and/or cooling costs, the system is also used as a barrier to, for example, particulate material, fumes, liquids in droplet form, insects, and noise.
Flexible strip door systems are typically made up of a plurality of flexible plastic strips, often clear so as to provide a see-through feature, having a width in a range of 4–16 inches, a thickness in a range of 0.060 to 0.160 inches, and a length which can vary from several inches to any length required to provide the desired barrier. The flexible plastic strips are most often hung from hangers having a horizontally oriented rod, or a series of evenly spaced horizontally projecting studs. In use of the rod system, loops are formed at tops of each plastic strip and the loops are slid successively over an end of the rod, in an abutting arrangement, in order to obtain the door barrier. In use of the system having projecting studs, evenly spaced apertures, which correspond to the spacing of the evenly spaced studs, are provided along a top edge portion of each strip and the strips can be easily arranged on the hanger by inserting the studs through the apertures.
The stud-type hanger system is more advantageous as the strips can easily be arranged to have a pattern ranging from one in which longitudinal edges of the strips abut each other to a pattern in which portions of the strips overlap each other. With the stud-type hanger system, the overlap can be selected to be in any increment corresponding to the spacing of the studs. Another advantage of the stud-type system is realized when replacement of a few strips is necessary, as only the strips to be replaced need to be unfastened, while not disturbing the remaining strips. Depending on the amount of usage and the type of equipment passing through the barrier, replacement of individual strips is usually required over the life of the flexible strip door system.
Whether for a new installation or for replacing worn or damaged strips, inventorying, shipping and handling of the strips is difficult due to the often long length of each strip. For example a flexible strip door system for a warehouse loading dock might require strips which are 10 to 16 feet in length. Although the strips can be stacked upon each other, the excessive length makes handling of a large number of stacked strips difficult. Folding the strips is not a good solution, as it can result in permanent distortion to the shape of the strips, thus not providing a barrier having good sealing properties. Winding individual strips upon each other for shipping and handling is difficult and the resulting arrangement is awkward to handle.